A scalable vertical conveyor cyclically carries planters (i.e. trays) in a closed path through a sub-floor dark zone and an above floor illuminated zone. A dark zone, formed below a floor, provides a dark region that simulates nighttime. The rate of travel simulates a growing day, such as, but not limited to a 24 hour growing day. One or more lighting, irrigation and fertigation elements are provided in the illuminated zone. Optionally, the portion of the conveyor in the dark and illuminated zones are adjustable.